1. Field of the Invention
The present invention pertains to a gravel pack assembly for installation in a well having a tubing seal connected below the packer to permit rotary and reciprocal movement of an auger gravel pack screen during installation without permitting fluid flow through the packer bore in the event of an underbalanced or overbalanced condition in the well.
2. Background
Auger type gravel pack screen assemblies have become increasingly popular for installations where a gravel packing around a sand control screen is required to control the flow of sand and other solids particulates in fluid production wells. U.S. Pat. No. 5,036,920, issued Aug. 6, 1991 to Cornette, et al and assigned to the assignee of the present invention describes one embodiment of an auger type gravel pack screen and a method of installation. Although the auger type gravel pack screen is particularly advantageous for many sand control screen installations in wells, one problem which must be overcome during installation of an auger type gravel pack screen is the prevention of fluid flow both out of and into the gravel packing, that is, when the well is in an underbalanced or overbalanced fluid flow condition. It is difficult to provide a suitable fluid tight seal between spaced apart zones in the wellbore during the installation of an auger type gravel pack sand control screen due to the fact that the screen is preferably reciprocated in the well during the augering process. Although seal bore type packers may be installed in the well to control fluid flow between different zones, as the tubing string to which the gravel pack screen is connected is reciprocated through the packer, the packing or seal rings on the tubing string sub which engages the packer seal bore invariably moves into and out of the bore. This action often results in high velocity fluid flow in one or the other direction through the bore of the packer or other seal member. This fluid flow and the resultant pressure drop across the packing on the tubing sub can severely damage the packing and there is also the inevitable movement of fluid into an unwanted area of the wellbore. Accordingly, there has been a need to overcome the aforementioned problem associated with installing gravel pack screens and particularly auger type gravel pack screens. This problem is solved by the gravel pack screen assembly of the present invention.